Various forms of communications can be performed in packet-based networks, such as electronic mail, web browsing, file transfer, and so forth. With the increased capacity and reliability of packet-based networks, voice communications (along with other forms of real-time, interactive communications) have also become feasible. In such communications, voice and other real-time data are carried in packets that are sent across the network.
Various standards have been proposed for voice and multimedia communications over packet-based networks. One such standard is the H.323 Recommendation from the International Telecommunication Union (ITU). Another standard for voice and multimedia communications is the Session Initiation Protocol (SIP), as developed by the Internet Engineering Task Force (IETF). Generally, H.323, SIP, and other control protocols are used for negotiating session information to coordinate the establishment of a call session. Once negotiation setup has been completed, packetized media (including voice or other forms of real-time data) can flow between endpoints. A media transport protocol, such as the Real-Time Protocol (RTP), is used for conveying packetized media between the endpoints.
In some cases, it may be desirable to redirect a call from an originating terminal from one destination terminal to another destination terminal. For example, in some networks, an announcement server may first process an incoming call, with the announcement server playing a pre-recorded message and providing various options for selection by a user. The call is then redirected to another terminal or node. Conventionally, to redirect a call, control signaling is exchanged with the originating terminal so that the appropriate media path is established between the originating terminal and the destination terminal. In certain scenarios, the re-negotiation of media paths in mid-call (or post-setup) is a complex process that is not supported by less capable devices. It also potentially adds an undesirable increase in network traffic and delay in redirecting the call.